Plastic does not biodegrade. Every piece of plastic that humanity has ever made is still somewhere in the environment. Some of it is buried in landfills, some is recycled back into the system, but a lot ends up in the oceans. Rivers and streams pick up litter and deposit it at their terminus in the sea, wind picks up plastic wrappers and bags and blows them into the ocean.

When some plastics are left in the sun and sea for long they do break down, but not in a biodegradable way — they just become smaller pieces of plastic. If anything, this is a more dangerous form of plastic because it's just about impossible to clean up. Researches have studied water taken from the plastic gyre and found that microscopic pieces of plastic outnumbered plankton, the base of the sea web of life, 48 to 1. Let me say that again — there is forty eight times more microscopic pieces of plastic thank plankton in a huge swath of the Pacific Ocean.

de Rothchild is following on the heels of adventurers Markus Eriksen and Joel Paschal who completed a similar trip last from California to Hawaii. Their boat used 15,000 plastic bottles and the reused cockpit of a Cessna.